Control system



Feb; 19, 1963 c. w. SKELTON 3,078,353

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ATTORNEYS United States Patent ()fifice 3,078,353 Patented Feb. 19, 1963 3,tl78,353 CGNTRUL SlldTElt i Charles W. Shelton, lrving, Ten, assignor to Texas rnents Incorporated, Dallas, Ten, a corporation at Del-- aware Filed Feb. 25', 1958, tier. No. 717,497 Claims. (#31. Edit-1) This invention relates to a selective control system and a matrix switch for the control system.

The system according to the present invention controls a plurality of output stages simultaneously. Output stages can be actuated after independently selected intervals and the intervals can be varied in steps over a wide range, separately for each output stage. For example, one output stage can be actuated three seconds after a starting time, another actuated 210 seconds after the starting time, and another actuated 4-53 seconds after a starting time. According to the disclosed embodiment of the invention, the output stages can be actuated after the same or different intervals each of which can be independently selected to extend for a duration of from one second to 511 seconds in increments of one second.

Prior to the present invention systems were known to actuate output stages after diifer-ent intervals but the intervals were fixed and could not be varied.

The apparatus of the present invention provides selectively varied intervals by means of a matrix switch which can connect any one of a plurality of a first group of conductors to any one of a plurality of a second group or conductors. An output is taken from each stage of a transistor flip-flop binary counting chain and applied to a different conductor of the first group, and each of the second group of conductors of the matrix switch is connected to one of the output stages. When connection is made between one of the first group of conductors and one of the second group of conductors it is made through a diode to prevent sneak circuits. The connection is made by means of a small conductive bolt or screw and a conductive collar or washer that surrounds the bolt but is insulated from the threaded rod of the bolt. The head of the bolt is adapted to make contact with the conductive collar or washer when the bolt is screwed down. Current will flow from meet the first group of conductors through the body of the bolt to the collar or washer and through the associated diode to one of the second group of conductors. When the bolt is not screwed down, the head of the bolt will not be in contact with the conductive collar or washer and the circuit will be open.

The use of this kind of matrix switch permits selective connections to be made from a very small control board having very little weight. This is a substantial improvement over matrix switches of the prior art which are large and cumbersome. Since transistors are used for the active components of the system of this invention, the whole control system is small in size and weight.

Other objects and advantages of the invention will become readily apparent as the following description or" a preferred embodiment of the invention unfolds and when taken in conjunction with the drawings in which:

FIGURE 1 of the drawings shows a top view of the matrix switch according to the present invention;

FIGURE 2 is a view in cross-section illustrating how the connection is made between one of the conductors of one group to one of the conductors of the other group;

FIGURE 3 is a view in perspective showing a part of the matrix switch with the mounting base removed; and

FIGURE 4 shows a circuit diagram of the control system.

A preferred embodiment of the invention will now be described. As shown in FIGURE 2 each element of the matrix switch comprises a conductive threaded screw 12 which screws into a conductive receptacle 14. The receptacle 14 is mounted in an insulating mounting board 11 and a potting compound 15 secures the conductive receptacle 14 in position. The threaded body of the screw 12 passes through an opening 19 in the mounting board 11. A conductive washer or collar 13 is attached to the board 11 around the opening 19 on the upper side of the mounting board 11. The inner diameter of the collar 13 is sutficiently larger than the diameter of the threaded rod of the screw 12 to provide an appreciable air gap between these parts and electrically insulate one from the other. When the screw 12 is screwed down into the receptacle 14, the head of the screw 12 will come into contact with the collar 13 thus completing a conductive path from the conductive receptacle 14 to the conductive collar 13. When the screw 12 is screwed up out of the receptacle 14, the contact between the head of the bolt 12 and the collar 13 is broken and the conductive path between the receptacle 14 and the collar 13 is opened.

In the preferred embodiment of the invention seventytwo assemblies, each comprising a screw 12', a receptacle 14 and a conductive collar 13, are arranged in a rectangular array of nine rows and eight columns in the insulating mounting board 11, as shown in FIG. 1, and held by means of a potting compound 15. Each of the screws 12 will make contact with a collar 13 simply by being screwed down and will open this contact simply by being screwed out of contact therewith. A group of conduc tors 4143 are situated on top of the mounting board 11 running between the columns of the screw and collar assemblies 12 and 13. The conductors 41--48 and the collars 13 can be formed on the board 11 by printed or etched circuit techniques.

In FIGURE 3 the mounting board 11 and the potting compound 15 have been left out in order to illustrate the details of the assembly of the matrix switch more clearly. Another group of conductors 31-69 connect the rows of conductive receptacles 14 together. Only the first three conductors 3-1--33 are illustrated in FIGURE 3.

Each of the collars 13 are formed with a projection and a diode 16 electrically connects this projection to the adjacent one of the conductors 41-48. Thus, when one of the screws 12 is screwed down so that the head of the screw makes connection with the collar 13, then the associated conductor of the conductors 3139 is connected through the associated receptacle 14, bolt 12, collar 13, and the associated diode 16 to the associated one of the conductors 41-48. Any one of the conductors 3139 can thus be connected to any one of the conductors 41-48 simply by screwing down the proper screw 12.

Thus, there is provided a small lightweight compact matrix switch by means of which each of a first group of conductors can be connected to any combination of a second group of conductors. The switch is easily operated by non-skilled personnel and all that is needed for anyone to set the switch for operation is a screwdriver.

FIGURE 4 shows a circuit diagram of a matrix switch in combination with the system of the invention in which the switch is used. Here the conductors 3139 are shown vertically while the conductors 41-43 are shown horizontally. The switches 20 each comprise one of the receptacles 14, one of the screws 12 and one of the collars 13 in the arrangement illustrated in FIGURES 1 through 3. As is seen in FIGURE 4-, each of these switches 20 provides means to connect one of the conductors 3139 to one of the conductors 41-48 through one of the diodes 16, and by means of the switches 20, any one of the conductors 31-38 may be connected to 3 any one of theconductors 41-48. The diodes 16 have theircathodes connected to the respective one of the switches 20 and their anodes connected to the respective one of the leads 4148 so that current will flow only in thedirectionfromtheleads 41-,-.48 to theleads 3139. Each-of the,,conductors 31.39 is connected to the output of a separate-one of the.bistable flip-flops 21--29. For example, conductor- 31 is connected to the output of flip-flop 21,. conductor32 to the output of flip-flop 22, etc. The bistable fiipsflops 21-29 are connected together toform a binary counting chain as is disclosed in co-pending application of Charles W. Skelton et al., Serial No. 623,385, filed November 20, 1956, now. Patent No. 2,970,226, issued January 31, 1961. Each of the bistable flip-flops have a first stable state and a second stable state. Each preceding flip-flop has an output connected to each succeeding flip-flop. By this connection each succeeding flip-flop is actuated to change from one state to the other when the preceding flip-flop changes from its second stable stateto its first stable state. A pulse generaor 30applies pulses to the first bistable fiipflop 21 at a rate of one pulse per second. Every time a pulse is applied'from the pulse generator 20 to the flipfiop21the-fiip-fiop 21 will change from the stable state that it is in to the opposite stable state. Accordingly,

the flip-flop 21 will change back and forth between its first stable state and its second stable state completing one cycle every two seconds. This cycling of the flip-flop 21 actuates the second bistableflip-flop 22 causing the flipflop 22 to change back and forth between its stable states at half the frequency of the first flip-flop 21 or 1 cycle every 4 seconds and similarly each of the fiip fiops 23- 29 will be actuated-to change back and forth between 1 their stable states at half the rate of the preceding bistable flip-flop as 'was described in the above-mentioned Patent toCharles W.'Skelton et al. Eachof the bistable'fiipflops 21-491 applies a voltage to aseparate one of the conductors 3139. When one-of the bistable flip-flops 2129 is in the first stable state it applies a low voltage to the connected one of the conductors 31--39 and when the flip-flop is in a second stable state it applies a high voltage to the connected conductor. Each of the flipfiops 2129is provided with an emitter follower circuit to achieve a low impedance, output to the conductors 31-39. Each of the conductors 4148 is connected to a conductor '50 by means of one of the resistors 61-68. The conductor 50'has a terminal 40 to which a plus DC. voltage is applied. Each of the conductors 41-48 is connected to a different one of a group of output control stages 5158. Each of the output control stages will be actuated when the applied voltage from the respective one of the conductors 41-48. changes from a relatively low value to ahigher value. The output control stages may be fiip-flopswith a difierentiating capacitor and rectifier input of the type disclosed in the said Patent to Charles W. Skeltonet al. The output from these flipflops could control latching relays.

By means of thissystem each of the output control stagescan be simultaneously and individually controlled to be actuated after selected lengths of time from 1 second to 511 seconds. That is, by closing the proper switches 20 each of the control stages 51 through 58 can be actuated after an interval which can be independently selected for each unit.

Suppose, for example, that it was desired to actuate the first stage 51 aftera time interval of 21 seconds. First, the binary counting chain comprising flip-flops 2129 is cleared so that each flip-flop is in its first stable state. Next, the switches 20 which connect lines 31, 33 and 35 to line 41are closed. The stage -51 will not be actuated until the voltage on line 41 changesv from a low value to a higher value and this action will not occur until the flip-flops 21, 23 and 25 are all in their second stable state and apply high voltages to lines 31, 33 and 35. This is for the reason that if one or more of the flip-flops 21, 23 or 25 are not in their second stable states then current will flow from the plus DC. voltage source at terminal 40 through the resistor 61 over the respective diode 16 and switch 20 to the low impedance, low voltage applied from the flip-flop which is in its first stable state. Thisflow of current will cause a voltage drop through the resistor61 andthe voltage applied to the control stage 51 from line 41 will be low. If all three of the stages 21, 23 and 25 are in their second stable states a high voltage will be applied to lines 31, 33 and 35 and current will not flow from the terminal 40 through the resistor 61. Hence, when the binary counting chain goes into the condition whereby the flip-flops 21, 23 and25;

are all in their second stable states, the voltage on line 41 will rise to a higher value and the control stage 51 will be actuated.

to the flip-flop 21 at a rate of one pulse per second,

it will take exactly 21 seconds for the counting chain to achieve the condition in which the flip-flops 21, 23 and 25 are all in their second stable states. By selectively closing the other switches 20, connecting different combinations of lines 3l39 to line 41, the output control stage 51 can be actuated after any selected time interval, varying in steps of one second, from one second .to: 511.

seconds. Likewise, the other output control stages. 5258 can be actuated after selected time intervals by closing the proper remaining switches 20. Thus, from: a given starting time the stage 51 may be actuated after.

a desired interval, the stage 52 actuated after a different desired interval, the stage 53 actuated after still a different interval and so on down the line to the stage 58 selected time intervals.

T e matrix size may be increased to increase the num ber of control stages or the length of the maximum time interval. For more precise control, the size of the steps in the variation of the time interval may be decreased by increasing the rate at which pulses are applied to the flipflop 21'from the pulse generator 39. These and other modifications may be made without departing from the spirit and scope of the invention which is defined in the appended claims.

What is claimed is:

1. A matrix switch comprising a first group of conductors, a second group of conductors positioned across said first group of conductorsand normally insulated therefrom, a separate plurality of threaded conductive receptacles equal in number to the number of conductors in said second group connected to each of the conductors of conductors of said second group, a separate conductive screw threaded into each of said threaded receptacles and being normally insulated from the conductors of said second group, and a separate conductive means for making contact with each of said screws and being insulated from the conductors of said first group, each of said conductive means for making contact with the conductive screws threaded into the threaded receptacles of any one conductor of said first group of conductors being connected to adifferent conductor of said second group of conductors and contacting its associated screw only when said screw is screwed to a predetermined position.

2. A matrix switch comprising an insulating means, a first group of conductors mounted on said insulating means, a second group of conductors mounted on said insulating means crossing over said first group of conductors and spaced therefrom a separate plurality of threaded conductive receptacles equal in number to the numberof conductors in said second group connected'to; each of the conductors of said first group and being mounted on Starting with all of the flip-flops 21- 29 in their first stable states and with pulses applied menses said insulating means in spaced insulated relation from said second group, said insulating means having defined therein a separate hole in register with each of said threaded receptacles of each of said plurality of threaded receptacles, a separate conductive screw passing through each of said holes and being threaded into the threaded receptacle in register with each of said holes, and a separate conductive means for making contact with each of said screws and mounted on said insulating means in spaced insulated relation with the conductors of said first group, each of said conductive means for making contact with the conductive screws threaded into the threaded receptacles of any one conductor of said first group of conductors being connected to a different conductor of said second group of conductors and contacting its associated screw only when said screw is screwed to a predetermined position.

3. A matrix switch as recited in claim 2 wherein each of said conductive means surrounds one of said screws, is spaced for electrical isolation from the shank of said one of said screws, and makes contact with the head of said one of said screws only wh n said one of said screws is screwed to said predetermined position.

4. The matrix switch as defined in claim 1 wherein each of said conductive means includes a diode.

5. The matrix as defined in claim 2 wherein each of said conductive means includes a diode.

References Cited in the file of this patent UNITED STATES PATENTS 717,194 Hewlett Dec. 30, 1902 947,956 Agutter Feb. 1, 1910 2,064,736 Dahl Dec. 15, 1936 2,110,968 Blakeslee Mar. 15, 1938 2,172,218 Myiius Sept. 5, 1939 2,570,716 Rochester Oct. 9, 1951 2,613,287 Geiger Oct. 7, 1952 2,643,172 Reiss June 23, 1953 2,665,336 Saykay Ian. 5, 1954 2,686,299 Eckert Aug. 10, 1954 2,810,903 Lee Oct. 22, 1957 2,813,986 Dickinson et a1 Nov. 19, 1957 2,914,759 Deighton et a1. Nov. 24-, 1959 FOREIGN PATEIJTS 540,268 France Apr. 14, 1922 562,382 France Sept. 1, 1923 194,132 Switzerland Mar. 1, 1938 626,573 Great Britain July 18, 1949 926,796 Germany Apr. 25, 1955 

1. A MATRIX SWITCH COMPRISING A FIRST GROUP OF CONDUCTORS, A SECOND GROUP OF CONDUCTORS POSITIONED ACROSS SAID FIRST GROUP OF CONDUCTORS AND NORMALLY INSULATED THEREFROM, A SEPARATE PLURALITY OF THREADED CONDUCTIVE RECEPTACLES EQUAL IN NUMBER TO THE NUMBER OF CONDUCTORS IN SAID SECOND GROUP CONNECTED TO EACH OF THE CONDUCTORS OF SAID FIRST GROUP AND BEING NORMALLY INSULATED FROM THE CONDUCTORS OF SAID SECOND GROUP, A SEPARATE CONDUCTIVE SCREW THREADED INTO EACH OF SAID THREADED RECEPTACLES AND BEING NORMALLY INSULATED FROM THE CONDUCTORS OF SAID SECOND GROUP, AND A SEPARATE CONDUCTIVE MEANS FOR MAKING CONTACT WITH EACH OF SAID SCREWS AND BEING INSULATED FROM THE CONDUCTORS OF SAID FIRST GROUP, EACH OF SAID CONDUCTIVE MEANS FOR MAKING CONTACT WITH THE CONDUCTIVE 